The Predator is a funny-looking little airplane, only 27 feet long with what looks like an oversize head but in reality is a compartment for the Ku-band satellite dish, which receives instructions from a pilot and sends imagery back. It has a glider's high-aspect-
ratio wings. Big, slab-like tailplanes splayed downward complete the look of a hydrocephalic insect, especially when its spindly landing gear lowers for approach.
"This is the hardest thing I've ever had to fly," says Captain Craig Babbitt, a 29-year-old pilot who had been flying C-130s before signing up for a two-year tour with the Predator. "You're looking at numbers. [Even when flying on instruments] in an airplane, you have all your senses. Only one person has said he's done something harder, and that's a carrier landing."
The pilot in the ground control station flies the Predator as he would a conventional aircraft-with a stick in his right hand and throttle in his left-only instead of looking through a windshield, he's watching the 30-degree field of view from the aircraft's nose camera. One pilot compares the sensation to "driving your car with paper towel tubes over your eyes."
The pilot and sensor operator, who sit side by side in the control station, face two 20-inch screens, one above the other. On the upper screen, a map of the target area is displayed with a symbol of the aircraft superimposed on it. The pilots must keep the Predator within a certain corridor a few miles in width. The corridor is also displayed on the map. "We're not so much flying a heading," one pilot said, "as we are keeping the aircraft within the corridor on our map display." Once the pilots level off at altitude, an autopilot holds altitude and airspeed.
On the pilot's lower screen, symbols overlying the nose camera video report the transponder code, airspeed, angle of attack, altitude, and other information, such as engine manifold pressure. Two smaller screens show what are called variable-information tables, displaying the positions of the flaps, for example, and engine temperature. The ground control station replicates the environment of an aircraft cockpit. The biggest difference between the two is that the Predator's pilot can switch off with a replacement and go outside to stretch his legs.
At first, engineers at General Atomics Aeronautical Systems, Inc., the manufacturer of the Predator, tried landing the thing remotely by watching the aircraft from the ground, as hobbyists flying radio-controlled models do. "The attrition rate was much higher when we flew the aircraft externally for takeoff and landing," says Allen Isbell, a systems engineer with GA-ASI. "We found that involves a different skill set, and it was much more difficult to train someone to do that." With other UAV systems, a pilot stands outside during takeoff, flying the aircraft by remote control, then hands off to a pilot inside a control station, who monitors the systems during the cruise portion of the mission, then hands back to the pilot outside for landing. According to Isbell, there has sometimes been confusion over which pilot is actually in control. "So we migrated toward flying the system as one would a manned aircraft," he says.
To make that possible, pilots have to receive simultaneously the nose camera's video and telemetry reporting the aircraft's condition and attitude. The high data rates and wider bandwidth necessary for that transmission became available in the mid-1980s, when microwave communications matured. The pilot's inputs on the stick and throttle are transmitted to the aircraft through a C-band radio link. Once the Predator gets beyond the range of line-of-sight communications, pilot commands are sent by cable to a satellite transmitter/receiver that passes them via Ku-band to an Intelsat 602 communications satellite for transmission to the aircraft.
Even with high data rates, however, the aircraft can't send to the pilot that seat-of-the-pants feeling he gets as he flies: no rolling tendencies, no turbulence, no sense of the sink rate, no ground rush on landing. Pilots compensate by developing visual cues to get the aircraft on the ground smoothly: When the runway fills the bottom third of the screen, for example, you raise the nose to flare.
The telemetry will sometimes tell a pilot what he can't sense by watching the video. "When you're in the standard pattern," says Craig Babbitt, "you think the nose is down, but it's still climbing. So you push the nose down harder, but that's not a very comfortable feeling. I feel very confident with it, but I still don't trust it. It's so sensitive; five knots [of wind] is a big deal for this airplane."